Analogue systems

Is anyone using Cakewalk/Sonar with an AS midi/CV converter?
My Integrator will not register any signal output from my PC.  It does
fine with most other inputs (except a Novation controller).  There's
no data received at all.  Even if I run a signal into the AS via
another source, the signal will die at the Integrator as soon as the
PC is connected to this other source.
Channel settings are all fine, but there must be something I'm
missing.  Any suggestions?  

thanks